By Dr Ananya Mandal, MD
The vulva and the female external genitalia begins to develop while the baby is still within the mother’s womb. The development again gains acceleration during puberty when the female reproductive organs are exposed to female hormones like estrogen and there is appearance of the secondary sexual characters. Development of the vulva includes the following stages.
Embryonic or fetal development
Both the male and the female fetus for the first eight weeks of life have the same rudimentary reproductive and sexual organs. The hormones of the mother control their development. After this time the fetus begins to produce its own hormones and by the twelfth week male and female fetus start to appear physically different within the womb.
At the sixth week there is appearance of the genital tubercle develops in front of the cloacal membrane. The genital tubercle has a groove termed the urethral groove. This groove gives rise to the urogenital sinus that goes on to form the bladder and the urethra. On either side of the groove are the urogenital folds. There are two other folds or ridges on either side called the labioscrotal swellings.
At the third month of the pregnancy the genital tubercle becomes the clitoris. The urogenital folds become the ''labia minora'', and the labioscrotal swellings become the ''labia majora''.
The vulva of a newborn baby girl is swollen or enlarged because of its exposure to her mother's increased levels of female hormones via the placenta. The clitoris is proportionally larger than it is likely to be later in life. Within a short period of time as these hormones wear off, the vulva will shrink in size and return to normal appearance.
From the age of one until onset of puberty there are no changes in the appearance of the vulva. The external genitalia just grow proportionately along with the rest of the body.
Puberty marks the onset of secondary sexual characteristics. The structures of the vulva become proportionately larger and may become more pronounced. Pubic hair appears and the vulva becomes darker and pigmented. The pigmentation begins at the labia majora and spreads to the mons pubis. It may extend to inner thighs and perineum. The stages of pubic hair development are classified as Tanner stages of development.
Just before puberty the vulva appears to be positioned further forward than in adults. This reveals a larger proportion of the labia majora and pudendal cleft on standing. The mons pubis also enlarges and appears more prominent. Variations in body fat levels affect the extent to which this occurs.
During vaginal delivery
The vagina as well as the vulva needs to stretch out to allow the outward passage of the baby's head. This can result in tears in the vaginal opening, labia, and clitoris.
After the menopause, the levels of female hormones like estrogen declines. This leads to shrinking of reproductive organs. The mons pubis, clitoris and labia are all reduced in size in post-menopause.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)